In the proposed Program Project, Core C will be titled the Biomedical Core. It will be directed by Dr. William Strong, Charbonnier Professor of Pediatrics, Chief, Section of Pediatric Cardiology and Medical Director, cofounder and past Director of the Georgia Prevention Institute. The Core Co- Leader will be Dr. Gaston Kapuku, a cardiologist with a Ph.D. in physiology. Much of the proposed methodology in projects 1-3 involves noninvasive biomedical evaluations using state of the art instrumentation (e.g., echocardiography, impedance cardiography, ultrasound evaluation of arterial stiffness and endothelial function, dual-energy X-ray absorptiometry [DXA] of body composition) as well as evaluations requiring medical supervision (e.g., physical examinations, intravenous catheter insertions, cardiovascular [CV] fitness test). Therefore, Dr. Strong's expertise as Core Leader will be integral to the conduct of these studies. He will oversee evaluation procedures which will be handled on a daily basis by Dr. Gaston Kapuku. The Program Project will require reliable and valid instrumentation for the evaluation of cardiovascular reactivity and recovery to acute and extended laboratory behavioral challenges, cardiovascular morphology (e.g., left ventricular mass [LVM], relative wall thickness [RWT]) and function (e.g., LV systolic function, endothelium dependent arterial dilation [EDAD] to reactive hyperemia and arterial stiffness) and body composition (e.g., total % body fat, % fat free mass [FFM], bone density, central adiposity). Core C will be responsible for maintaining the reliability, precision, calibration and validity of all equipment and the integrity of the measurement protocols. Additionally, Core C will be responsible for establishing the feasibility of utilization of new validated instrumentation which may become available during the Program Project. Core C will serve the entire Program and will interact closely with component projects 1-3.